<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        var year=prompt('请输入您想判断的年份');
        if(year % 4 == 0 && year % 100 != 0 || year % 400==0){
            alert(year+'是闰年');
        }else {
            alert(year+'是平年');
        }
    </script>
</head>
<body>

</body>
</html>